1. Field of the Invention
The subject invention relates to a heating, ventilation, and air conditioning (HVAC) system being operable in a fresh air mode and a recirculation mode for use in a vehicle having a passenger compartment with a front and a back and having a dashboard located in the front of the passenger compartment.
2. Description of the Related Art
Various heating, ventilation, and air conditioning (HVAC) systems being operable in a fresh air mode and a recirculation mode are known to those skilled in the art. These HVAC systems are used in vehicles having a passenger compartment with a front and a back. These vehicles include a dashboard located in the front of the passenger compartment. A blower is in fluid communication with the passenger compartment for circulating air from outside the vehicle into and through the passenger compartment in the fresh air mode and for recirculating air from within the passenger compartment in the recirculation mode. The systems also include a heating, ventilation, and air conditioning (HVAC) module in fluid communication with and downstream of the blower for warming and cooling the air to be circulated through the passenger compartment in both the fresh air mode and the recirculation mode. The blower has a first inlet duct for drawing air from outside the vehicle and a second inlet duct for drawing air from within the vehicle. The HVAC module has outlets for venting the air into the vehicle. Typically, there is a defrost duct venting air out above the dashboard, a panel outlet venting air out the front of the dashboard, and a floor outlet venting air out below the dashboard.
When the HVAC system is operated in fresh air mode, air enters the vehicle through the first inlet duct and is vented through the outlets. The air exits the vehicle from the rear providing continuously fresh air throughout the passenger compartment. In recirculation mode, air is drawn from within the vehicle through the second inlet duct below the dashboard. The air is vented back into the vehicle through the outlets. However, in recirculation mode, when the air is vented through the floor outlets, the air is immediately drawn back into the second inlet duct. This short circuits the airflow within the passenger compartment and prevents the air from circulating through the entire passenger compartment. Therefore, additional time is required to obtain a desired temperature of the air and vent the air throughout the passenger compartment.
It would be advantageous to provide a HVAC system that continues to circulate air throughout the passenger compartment while in recirculation mode. It would also be advantageous to provide the HVAC system having an improved warm-up rate of air within the passenger compartment while operating in the recirculation mode. Further, it would be advantageous to provide an HVAC system that has improved airflow across a windshield of the vehicle to prevent fogging of the windshield.
The subject invention provides a vehicle having a heating, ventilation, and air conditioning (HVAC) system being operable in a fresh air mode and a recirculation mode. The vehicle includes a passenger compartment having a front and a back and a dashboard located in the front of the passenger compartment. The HVAC system includes a blower in fluid communication with the passenger compartment for circulating air from outside the vehicle into and through the passenger compartment in the fresh air mode and for recirculating air from within the passenger compartment in the recirculation mode. The HVAC system further includes a heating, ventilation, and air conditioning (HVAC) module in fluid communication with and downstream of the blower for warming and cooling the air to be circulated through the passenger compartment in both the fresh air mode and the recirculation mode. The system includes an inlet duct in fluid communication with and upstream of the blower and located above the dashboard for drawing air from the passenger compartment above the dashboard and through the blower and the HVAC module in the recirculation mode.
While in recirculation mode, air is being vented into the passenger compartment through the floor outlets and drawn into the inlet duct located above the dashboard. This forces the air to flow up and around the dashboard and throughout the passenger compartment. The inlet duct above the dashboard does not create a short circuit in the airflow within the passenger compartment during recirculation mode. By forcing the air to flow throughout the passenger compartment, the air has an improved warm up rate, which improves the level of the occupant""s comfort. The inlet duct above the dashboard also improves the flow of air across a windshield of the vehicle to prevent fogging of the windshield.